| 摘要 |
In conventional processes for producing a grain-oriented electromagnetic steel strip or sheet, the carbon and silicon content of the starting material is such that alpha - gamma transformation takes place, said transformation formerly being belived to play an important role in, for example, the formation of AlN. Recently, attempts have been made to reduce the carbon content so as to simplify decarburization-annealing, but these attempts have not been successful. In the present invention, (1) an extremely low carbon content (C</=0.02%) and an extremely low sulfur content (S</=0.015%), as well as a low heating temperature of the starting material, and (2) a temperature gradient of at least 2 DEG C. per centimeter, which is generated parallel to the sheet surface and under which the growth of secondary recrystallized grains is completed, are combined. As a result of such combination, the following advantages are attained: (1) secondary recrystallization is attained without alpha - gamma transformation taking place; (2) a high magnetic flux density is attained; (3) a continuous-casting machine can be directly combined with a continuous hot-rolling mill; (4) decarburization-annealing can be simplified; and (5) no molten slag is formed during heating of a steel slab. |
